On 3/30/22 3:52 PM, Sidhartha Kumar wrote:

Print two possible reasons /sys/kernel/debug/gup_test cannot be opened to help users of this test diagnose failures.

Thank you for the patch to improve rather cryptic error messages.

Signed-off-by: Sidhartha Kumar sidhartha.kumar@oracle.com Cc: stable@vger.kernel.org # 5.15+

---

tools/testing/selftests/vm/gup_test.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/vm/gup_test.c b/tools/testing/selftests/vm/gup_test.c index fe043f67798b0..c496bcefa7a0e 100644 --- a/tools/testing/selftests/vm/gup_test.c +++ b/tools/testing/selftests/vm/gup_test.c @@ -205,7 +205,9 @@ int main(int argc, char **argv) gup_fd = open("/sys/kernel/debug/gup_test", O_RDWR); if (gup_fd == -1) {

• perror("open");
  

• perror("failed to open /sys/kernel/debug/gup_test");
  

• printf("check if CONFIG_GUP_TEST is enabled in kernel config\n");
  

• printf("check if debugfs is mounted at /sys/kernel/debug\n");
  

Instead of adding 3 messages in a row, please check the errno to figure out why it failed and print an appropriate message.

If open fails because CONFIG_GUP_TEST is not enabled, the test should skip the test instead of fail. Failing will indicate a test failure which is not the case. The test couldn't be run due to unmet dependencies.

This test requires root access. A check for root privilege and skip the test for the same reason stated above.

exit(1);

}

Please send v2 with these changes.

thanks, -- Shuah